Howdo folks,
So I have my data (attached). There are two columns I'm interested in;
"algname" and "dur". I'd like to know how dur changes with algname.
algname is nominal and there are 7 possibilities. There are two more
nominal independents, "task" and "id", so my model is:
dur ~ algname+task+id
From the research I've done, a TukeyHSD seems to be what I need, so I do:
TukeyHSD(aov(dur ~ algname+task+id, cstats), ordered=T)
But I get this back:
Error in rep.int(n, length(means)) : unimplemented type 'NULL' in 'rep'
In addition: Warning messages:
1: non-factors ignored: task in: replications(paste("~", xx), data = mf)
2: non-factors ignored: id in: replications(paste("~", xx), data = mf)
Can anyone shed any light on the situation?
Gav
TukeyHSD fails on my data
3 messages · Gav Wood, Brian Ripley
We don't have the data (nothing useful was attached - see the posting guide for what you can attach), but it looks like you should be using the 'which' argument to TukeyHSD.
On Mon, 7 May 2007, Gav Wood wrote:
Howdo folks,
So I have my data (attached). There are two columns I'm interested in;
"algname" and "dur". I'd like to know how dur changes with algname. algname
is nominal and there are 7 possibilities. There are two more nominal
independents, "task" and "id", so my model is:
dur ~ algname+task+id
From the research I've done, a TukeyHSD seems to be what I need, so I do:
TukeyHSD(aov(dur ~ algname+task+id, cstats), ordered=T)
But I get this back:
Error in rep.int(n, length(means)) : unimplemented type 'NULL' in 'rep'
In addition: Warning messages:
1: non-factors ignored: task in: replications(paste("~", xx), data = mf)
2: non-factors ignored: id in: replications(paste("~", xx), data = mf)
Can anyone shed any light on the situation?
Gav
Brian D. Ripley, ripley at stats.ox.ac.uk Professor of Applied Statistics, http://www.stats.ox.ac.uk/~ripley/ University of Oxford, Tel: +44 1865 272861 (self) 1 South Parks Road, +44 1865 272866 (PA) Oxford OX1 3TG, UK Fax: +44 1865 272595
Prof Brian Ripley <ripley <at> stats.ox.ac.uk> writes:
We don't have the data (nothing useful was attached - see the posting guide for what you can attach), but it looks like you should be using the 'which' argument to TukeyHSD.
But I get this back:
Error in rep.int(n, length(means)) : unimplemented type 'NULL' in 'rep'
In addition: Warning messages:
1: non-factors ignored: task in: replications(paste("~", xx), data = mf)
2: non-factors ignored: id in: replications(paste("~", xx), data = mf)
Can anyone shed any light on the situation?
The problem was, as Jeff Laake adroitly pointed out, I had failed to tell R that the latter two independents were factors. It was easliy fixed with as.factor(). Thanks folks, Gav